Power transmission belt



Novy25, 1941. J. Hf WILSON POWER TRANSMISSION BELT Filed NOV. 16, 1959 Patented Nov. 25, 1941 UNITED STATES PATENT OFFICE POWER TRANSMISSION BELT Application November 16, 1939, Serial No. v304,846

Claims.

The present invention relates to belts for -thetransmission of power and particularly to power transmission belts of the multiple V-belt type. It has heretofore been suggested that by the use of a. plurality of relatively small belts of V- shaped cross-section la'rge amounts of power can be readily and economically transmitted from one grooved pulley to another and the so-called multiple V-belt drive is widely used for communicating power or torque from one shaft to another in the driving mechanisms of numerous types of machines. Each V-belt of a multiple V-belt drive is laterally compressible or distortable, all V-belts of any one drive being fabricated, in the general case, of fabric sheets and cords embedded l in soft rubber.

In theory, as is well-known, the several belts of a set of V-belts automatically adjust themof these V-belts but which connecting means does not interfere in any respect with the independent action of the individual yV-belts, each belt being left free to accommodate itself by lateral delformation or compression, under tension, to the pulley groove in which it is placed so Vthat the tensions in the several belts of the drive automatically equalize themselves as before. Therefore, the interconnecting means employed in accordance with my invention is of such character that it will take substantially no tension but is relatively stiff in a direction transversely of the drive. Most conveniently the V-belt connecting selves in the grooves of the pulleys about which Y they pass, because of their transverse resiliency, the result being that all V-belts of a set are caused to pull equally and the possibility of slippage of one or more belts, Aand overloading of others, eliminated.

It is frequently found however that, even when the V-belts of a set of such V-belts are identically matched, there will be a tendency for one or more of the belts of the set to whip or vibrate excessively, substantially more than the other belt, or other belts, of the set. While such whipping or vibration is not serious or destructivev in itself, nevertheless it sometlxnes causes one or more belts of a set to eventually turn angularly in the pulley groove or grooves in which normally positioned so that the drive loses part of its effectiveness and one or more belts caused to wear excessively. Likewise a widely vibrating belt may even be caught between an adjacent belt and the pulley around which both belts are passing, with Vthe result that both such belts are immediately` means may comprise a rubber and Vfabric band to which two or more V-belts may be secured. Both V-belts and band are continuous and as the V- belts are likewise preferably made of fabric sheets and cords embedded in soft rubber the V- beltsl may be vulcanized to the band. Advantageously the band may have a base of interwoven threads or cords, including warp threads and cross or woof threads, the warp threads being looped or having slack portions which will merely destroyed and the drive seriously damaged orA connecting means or web which positively connects two or more V-belts of a drive -together in such manner as to prevent whipping and turning tend to straighten out when the band is placed under tension but which will not be stretched to such an extent as to become straight or taut and hence placed in substantial tension.

The invention, however, is not limited the use of any particular kind or type of connecting web or member and, within the import of the invention, any such member which will positively connect two or more V-belts so as to prevent one or more of such belts from whipping relatively to the remainder, or which will prevent any belt or belts from overturning, while at the same time Ibeing of such character as tok transmit no tensional forces, may be employed.

One embodiment of the invention will be disclosed by way of example but it will be appreciated that numerous modified forms may be employed with diii'erent types of drives.

In the drawing, in which a preferred form of the invention is disclosed:

Figure 1 is a partial axial section through a pulley having two belt receiving grooves, V- shaped in transverse section, a belt driving- -means of the improved type beingshownvto be in operative engagement therewith:

Figure 2 is a, plan View, partially broken away, of a section of the v-belt connecting band shown in Figure l;

`fiigure 3 is a section on line 3-3 of Figure 2; an

Figure 4 shows in plan, partially broken away,

35 a complete power transmission drive including `a drive of the type 'the type just described.

the driving and driven pulleys and the interconnecting flexible v-belt driving means.

Portion of a driving or pulley is shown to be provided with two peripheral outwardly opening V-shaped grooves II. Within each groove is a V-belt I2, these belts being identical in construction. A very satisfactory type of V-belt heretofore widely employed in described comprises longitudinally extending cords or fabric sheets embedded in relatively soft rubber. The V-belts I2 driven pulley is illus- Y trated in transverse section in Figure 1 and this ing band illustrated. economically and may be readily attached to any number of individual V-belts by vulcanization.

Having thus described the invention, what is claimed as new and desired to be obtained by Letters Patent is:

i. A belt for the transmission of power comprising a plurality of V-belts each having oppositely facing side driving surfaces and being elastic so as to be transversely deformable, and longitudinally extensible means connecting said V- belts to prevent whipping or rotation of one -V- shown in the drawing by way of example are 'of Each V-belt I2 is connected to a transverse band I3 which band is also fabricated of fibrous material embedded in soft rubber, the inner surface of the band and the outer surfaces of the V-belts vI2 being vulcanized together so that the band and the V-belts together comprise one unitary endless driving belt. In Figun 4 it willbe observed that the pulley Il is shown to be connected to the pulley IIIA by Ithree or more V-belts interconnected by a single band so as to form one endless flexible driving means. If desired, however, a drive means may be substituted which comprises V-belts arranged in interconnected pairs, or in interconnected groups of three.

The manner in fabricated may be widely varied but I prefer to employ one fabricated substantially as indicated in the drawing, the band having woof cords I5 disposed as shown in Figures 2 and 3 and one or more longitudinally extending fabric strips I8 disposed to overlie the transversely extending reaches of the groups of woof cords I5 and drooping or sagging downwardly between these groups of woof cords, as shown most clearly in Figure 3. The layers of fabric and the Woof cords shown are embedded in soft rubber and it will be perceived that, when the band is subjected to longitudinal tension, it will readily stretch without offering much resistance, the warp fabric simply tending to straighten out but never becoming taut. The Woof cords impart some transverse stiffness to the band, ciently stiff transversely elements or V-belts I2 in substantial parallellism the band being suili-v to maintain the tension belt relatively to another, said means freely permitting deformation of the individual V-belts.

2. A belt for the transmission of power comprising a plurality of v-beits each having oppositely facing side tic and transversely deformab1e,'and a flatband bridging said V-belts and to which band each V- belt is secured, said band being freely extensible longitudinally for the purpose set forth.

3. A belt for the transmission of power cornprising a plurality of V-belts each having oppositeiy facing side driving surfaces and being elastic and transversely deformable, and a fiat band bridging said V-belts and to which band each V- belt is secured, said band being composed of rubber and fiber and being freely, extensible longitudinally.

4. The combination set forth in claim 3 in which both the V-belts and the band are composed of rubber and fabric and are vulcanized together.

5. A belt for the transmission of power comprising a flat band portion and a plurality of V- portions, all such portions being fabricated of fiber and rubber vulcanized together, the V-portions being transversely resilient and the band portion being readily extensible longitudinally.

6. A belt for the transmission of power comprising a flat bandportion and a plurality of V- portions, all such portionsbeing fabricated of fiber and rubbervulcanized together, the V-portions being transversely resilient and the band at all times. The connecting band I3, and preferably also the V-belts I2 are covered exteriorly with a layer of bias cut lightweight fabric which is readily extensible and offers no resistance Ato A cillation of the V-belts and preventing any V-- portionbeing-readily extensible so as to take little or no'load, while effectively preventing any substantial relative movement-,of said yV-portions transversely of the belt.

'1. A b'eltfor the transmission lfof -power .comprising a pluralityjof V-belts each'y having oppositely facing-side driving surfaces and'being elastic so as to be transversely longitudinally extensible .exible element to which deformable, and a bothV-belts'f are secured, whipping or rotation belt to which it is attached from turning over,v k

likewise having the capacity to readily flex when passing around pulleys, and to -easily stretch.

longitudinally so that it does not modify'in any way the work oi the tension elements of the drive, i. e., the V-belts. These V-belts function "independently insofar as they transmit tensional forces independently of each other and independently of band I3, and accommodate themselves to the grooves in which they are received so as to transmit equal forces, exactly as before. It will be clear to one skilled in the art that other types of connecting bands or V-belts connecting means may be employed, likewise relatively stiff transversely and limp or without material strength longitudinally. That form of connectof one V-'belt relatively tov another lbeing, prevented by said member.

.8. A belt for the transmission of power comprising a plurality of V-belts 'which aresubstantially non-extensibleand a readily extensible element to which said V'belts are secured, for the 'purpose set forth. 'i

9. The combination set forth in claim 3 in which the band is composed of a warp which overlies Woof cords, both the warp and the woof cords being' embedded in rubber.

10. The combination set forth in claim 3 in which the band comprises spaced bundles of -woof cords, and a warp disposed thereover, the warp sagging intermediate the bundles ofv woof cords and both warp and woof being embedded in rubber.

JOHN HART WILSON.

however, may be producedv driving surfaces and being elas- 

